function expandedForm(num) {
    var len = num.toString().length
    return num.toString().split("").map((e,i)=>{return e!=0?e.padEnd(len-i,0):""}).filter((x)=>{return x!=""}).join(" + ")
}
console.log(expandedForm(70304));
let str = "12334".split("")
delete str[2]
console.log(str);